Problem: $ { \left[\begin{array}{rr}{0} & {0} \\ {4} & {-1}\end{array}\right]-\left[\begin{array}{rr}{0} & {4} \\ {1} & {1}\end{array}\right] = {?} } $
To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{0}-{0} & {0}-{4} \\ {4}-{1} & {-1}-{1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{0} & {-4} \\ {3} & {-2}\end{array}\right]}$